Here's the first mainstream Hollywood film about the CIA's practice of "extraordinary rendition": that is, kidnapping terrorist suspects and flying them to states that tolerate extreme interrogation amounting to torture. This movie is composed in the increasingly familiar international hectic-mosaic style, with a note of justified paranoia, featuring an ensemble network of half-a-dozen or so separate lives, from the highest to the lowest, the mightiest to the most powerless. There are tense scenes in Washington DC and other American locations, interspersed with crowded, chaotic moments out there in the Islamic world, with subtitled dialogue. (The poster designs for this emerging genre tend to show the cast in a scattered, disorientated array of frames: good characters tensely on phones, desperate for information, out of the loop.)

It's a structural device that implicitly carries the rational lesson that the US is not an island entire of itself, to paraphrase John Donne, that its actions have consequences for other people's lives, and are themselves determined by factors outside its borders. It also asks the audience to consider that the natives of other countries have families and feelings, too. There's a decency in this, but also a naivety and a moral equivalence: beneath the tangled web, there's a simple fence-sitting need for balance at all costs.

In terms of star status and empathy, Reese Witherspoon is here probably first among equals, playing Isabella, the heavily pregnant wife of an Egyptian-born chemical engineer, Anwar El-Ibrahimi (Omar Metwally). On the most debatable evidence, Anwar is suspected of aiding a suicide-bombing cell in a country specified in the script only as "north Africa" and whose horrible handiwork we see in the opening scene, fatefully killing an American intelligence agent, among dozens of other "north Africans". Anwar is snatched on his way back to Chicago from an innocuous business meeting and, hooded and shackled, finds himself in a prison cell in that same vaguely delineated country.

All this is on the orders of CIA dragon lady Corrine Whitman, played by Meryl Streep with much pursing of lips and removal of reading glasses. She's a badass patriot, contemptuous of the surrender-monkeys and her attitude is not so much take no prisoners, but take loads of prisoners and ship them out to the developing world for toenail-removal. The prisoner's wife, Isabella, finds herself in the painful position of having to beg for help from ambitious senatorial aide Alan Smith (Peter Sarsgaard) the former boyfriend whose heart she broke by getting married to Anwar in the first place. (Surely being husband to Reese Witherspoon is proof enough of all-American innocence, incidentally, like Arthur Miller seeing off the McCarthyites by being married to Marilyn Monroe?) Jake Gyllenhaal is Douglas Freeman, the idealistic young CIA agent who is sickened by the torture he witnesses, and decides to take action.

These torture scenes are grim. No punches are pulled. The technique of choice is waterboarding, and the film demonstrates how this is done for those of us who weren't quite sure. It is a quasi-drowning ordeal achieved by strapping the victim to a board, putting a hood over his head, tipping him back and then pouring water continuously on to his face so that the wet material slops down into his mouth and nostrils and he is unable to breathe, and overwhelmed with terror and disorientation. (Robert Harris, in his new thriller The Ghost, says that in 1947 a Japanese officer was convicted of using waterboarding on a US civilian and sentenced to 15 years' hard labour for a war crime. Harris also says that waterboarding victims generally last 14 seconds before giving in; the record is 150 seconds by the alleged 9/11 mastermind Khalid Sheik Mohammed, a feat of endurance that reputedly won the grudging admiration of his CIA captors. I wasn't timing it, but in this movie Anwar manages around the 14-second standard.)

But does waterboarding get facts, foil plots and save lives? Corrine Whitman angrily maintains that it does, but Douglas quotes Portia in The Merchant of Venice; rendition victims "speak upon the rack,/ Where men enforced do speak anything."

Under the direction of Gavin Hood, the performances are heartfelt enough, and Kelley Sane's script is earnestly even-handed with a line in the dialogue noting that rendition began "under Clinton". There's also a clever time-slip narrative trick revealing that a sub-plot has in fact been unspooling in flashback.

But infuriatingly, the movie fudges the most important issue, with a fundamental flaw that goes to the heart of the matter: the question of whether the CIA's phone-record evidence against Anwar is sound or not. If it's all just a mistake, then how can such a mistake be made? The question is not satisfactorily answered, and the sleight-of-hand intended to distract you from this fact simply fails to work. It's a decent enough effort, though. "This is my first torture" says a stunned Douglas to his acid-tongued superior. Just saying the word out loud inflicts an awful wound.